Motorcycling Australia Museum

1958 500cc AJS 18CS Scrambler

Brute strength

After a year in Europe where he competed in moto cross and in the 1957 International Six Days Trial with compatriots Tim Gibbes, John Rock and Roy East, Les Fisher sailed for home, bringing this AJS 18CS with him. Identical to its Matchless brother (both AJS and Matchless were produced by Associated Motor Cycles or AMC) in all respects except the shape of the timing case and the petrol tank colour, the AJS was one of the final examples of the big, heavy British four strokes that were soon to be rendered obsolete by the new generation of two strokes.

The 86mm x 86mm bore and stroke all-alloy engine was a willing performer, but in a machine that weighs 155 kilos, the most crucial factor was the strength and fitness of the rider. Suspension travel is just 75mm at the front and slightly less at the rear. Still, in the late 1950s, the AJS 18CS (or the Matchless G80CS) was a weapon in the right hands. Works riders Dave Curtis, Brian Stonebridge and Geoff Ward were tough men to beat – the rivalry between the AMC and BSA factories always the main attraction at ‘scrambles’ of the day. In standard catalogued form, the 18CS ('C' representing Competition) was supplied without air filtration of any kind. Indeed, the placement of the oil tank directly in front of the carburettor precluded the use of any impediment to incoming rubbish, so a common practice was to convert the left-side toolbox into an oil tank. This was done by welding the seams closed on the tool box, sticking in a spout and filler cap, and adding the necessary hoses and inlet/outlets. This allowed an air filer, of sorts, to be mounted on the right side where the oil tank used to be. On this machine, carburation is via an 1 3/8 inch Amal GP with remote float, although an Amal Monobloc was the standard fitting.

Back in Australia, one of Fisher’s first outings on the AJS was the Australian Scrambles Championships at Royal Park, Adelaide. The competition was tough, with returning ‘internationals’ Charlie West, Ray Fisher and Roy East all taking titles, but Les brought the bike home in third place in the 500cc Championship. Soon after, the AJS was sold to Sydney rider Bill Larue who raced it mainly on dirt short circuits for a few years before selling it to Keith Shrimpton. In 1966 it was acquired in a rather dilapidated state by Charlie Scaysbrook. The engine’s weak point was the timing side main bearing, which usually collapsed, taking most other major components with it. Later engines, sold as the Matchless G85CS, had much-strengthened bottom ends, with a Norton gear-driven oil pump replacing the old reciprocating design that dated back to the 1920s. As purchased, the entire bottom end, including the crankcases of the ex-Fisher AJS were scrap, but a new set of flywheels was turned up, a 7R AJS conrod fitted and replacement crankcases obtained from the UK.

The rebuild was completed just in time for the 1966 Australian Scrambles Championships at Christmas Hills in Victoria where Charlie’s son Jim rode the bike to tenth place in the Senior title. In it’s next outing, at Wollongong, the frame diamond broke clean in half, and the old warrior was dragged into the shed and dismantled. The components of the bike lay around for nearly twenty years in boxes and buckets until a replacement frame diamond was procured. The rebuild itself took a few years, but the completed machine is a joy to behold and is in completely original specification, right down to the Dunlop Sports tyres that are correct for the period. Very few of these bikes survive in complete form because the engines and gearboxes were generally plundered in the late 1960s to be used in Rickman Metisse frame kits. English tuner Jack Emmot even produced a version with the fins shaved off and compression raised to astronomical levels for use on British speedways and grass tracks.

Today the AJS is a reminder of what was considered top tackle before tracks were littered with stutters, quads and tabletops - when riders wore pudding basin helmets, gas goggles, and leather britches.